Treatment In A Magnetic Field Patents (Class 148/103)
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Patent number: 5792284Abstract: Magnetostrictive powder composite and method for the manufacturing of the magnetostrictive powder composite. The composite comprises magnetostrictive powder grains with chemical composition (RE).sub.x T.sub.1-x, where RE represents one or a mixture of several rare earth metals, T represents iron, nickel, cobalt, manganese or a mixture of these metals and x represents atomic fraction assuming a value between 0 and 1, whereby the grains are held together by a binder. The magnetostrictive grains constitute greater than 60 percent by volume of the composite. The composite is produced by pressing together magnetostrictive powder grains and the binder. Isostatic pressure may be used in the pressing step.Type: GrantFiled: May 15, 1995Date of Patent: August 11, 1998Assignees: Fox Technology KB, Proengco ABInventors: Tord Cedell, Lars Sandlund
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Patent number: 5788782Abstract: It is an object of the present invention to provide R-Fe-B permanent magnet materials having a good oxidation resistance and magnetic characteristics, and a process of producing the same capable of pulverizing efficiently, whereby an R-Fe-B molten alloy having a specific composition is casted into a cast piece having a specific plate thickness and a structure, in which an R-rich phase is finely separated below 5 .mu.m, by a strip casting process, the cast piece is subjected to a Hydrogenation for spontaneous decay, and thereafter, an alloy powder is dehydrogenated and stabilized for pulverization so as to fractionize crystal grains of a main phase constituting an alloy ingot, thereby the powder having a uniform grain distribution can be produced at an efficiency of about twice as much as the conventional process, and the R-rich phase and an R.sub.2 Fe.sub.Type: GrantFiled: August 9, 1995Date of Patent: August 4, 1998Assignee: Sumitomo Special Metals Co., Ltd.Inventors: Yuji Kaneko, Naoyuki Ishigaki, Koki Tokuhara
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Patent number: 5690752Abstract: A permanent magnet is obtained by pulverizing, molding and sintering a starting material containing an alloy ingot. The alloy ingot contains not less than 90% by volume of columnar crystals each having a columnar crystal grain size of 0.1 to 50 .mu.m along a short axis thereof and a columnar crystal grain size of larger than 100 .mu.m and not larger than 300 .mu.m along a long axis thereof, and is obtained by uniformly solidifying by a single roll method a molten alloy containing 25 to 31% by weight of a rare earth metal, 0.5 to 1.5% by weight of boron and iron under cooling conditions of a cooling rate of higher than 500.degree. C./sec. and not higher than 10,000.degree. C./sec. and a supercooling degree of 50.degree. to 500.degree. C.Type: GrantFiled: July 27, 1995Date of Patent: November 25, 1997Assignee: Santoku Metal Industry Co., Ltd.Inventors: Kazuhiko Yamamoto, Yuichi Miyake, Chikara Okada
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Patent number: 5666635Abstract: This invention, using finely ground powders obtained by either a ingot grinding method, a Ca reduction diffusion method or a strip casting method, proposes a fabrication method for high-performance R--Fe--B permanent magnets with excellent press packing characteristics, a high degree of orientation of the magnetization direction of each crystallite and a total sum of A, (BH)max (MGOe) and B, iHc (kOe), A+B greater than 59.5. Here, cast alloys or ground alloys are coarse ground by mechanical grinding or by a H.sub.2 absorption and decomposition method, and then fine ground by either mechanical grinding or by a jet mill grinding process to yield R--Fe--B fine powders with an average particle size of 1.0 .mu.m.about.10 .mu.m. These powders are then packed into a mold at a packing density of 1.4.about.3.5 g/cm.sup.Type: GrantFiled: September 6, 1995Date of Patent: September 9, 1997Assignee: Sumitomo Special Metals Co., Ltd.Inventors: Yuji Kaneko, Naoyuki Ishigaki
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Patent number: 5650021Abstract: It is an object of the present invention to provide a method of producing sintered- or bond- rare earth element.iron.boron magnets obtainable easily and superior in magnetic properties with stable performance. The method of producing sintered rare earth element.iron.boron magnets according to the present invention is characterized by that it comprises steps of mixing in a scheduled ratio an acicular iron powder coated with a coating material, a rare earth element powder coated with a coating material and a boron powder coated with a coating material, and subjecting the mixture to compression molding followed by sintering of the molded mixture in the presence of a magnetic field. The method of producing bond rare earth element.iron.Type: GrantFiled: September 25, 1995Date of Patent: July 22, 1997Assignees: Kawasaki Teitoku Co., Ltd., Komeya Inc., Sanei Kasei Co., Ltd.Inventor: Yasunori Takahashi
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Patent number: 5641363Abstract: In the manufacture of a rare earth sintered magnet of the Nd.sub.2 Fe.sub.14 B system, closed voids are formed in the magnet in a predetermined fraction to minimize shrinkage. Unlike open voids or pores in conventional semi-sintered magnets, the closed voids do not incur magnet corrosion since they do not communicate to the magnet exterior. By minimizing shrinkage during sintering in this way, a ring or plate-shaped thin wall anisotropic magnet can be prepared without machining for shape correction, achieving a cost reduction and a productivity improvement. Since a high density compact has a high deflective strength, it is easy to handle, minimizing cracking and chipping between the compacting and sintering steps.Type: GrantFiled: December 27, 1994Date of Patent: June 24, 1997Assignee: TDK CorporationInventors: Akira Fukuno, Hideki Nakamura, Gouichi Nishizawa
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Patent number: 5631093Abstract: Nonmagnetized permanent magnet material is heated in a pattern by a laser beam to a localized temperature above the Curie point or a temperature sufficient to reduce the coercivity sufficiently for an external field to magnetize the pattern in the direction of the field. Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength. Alternating pole magnets of this type can be used for stepper motor magnets.Type: GrantFiled: November 8, 1991Date of Patent: May 20, 1997Assignee: General Motors CorporationInventors: Thomas A. Perry, John R. Bradley, Thaddeus Schroeder, Carlton D. Fuerst
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Patent number: 5624503Abstract: A process for producing a magnet in which the content of anisotropic magnet powder is from 95 to 50% by weight. The process includes the following steps. A powder mixture composed of the anisotropic magnet powder and solder powder containing isotropic magnet powder as a main constituent thereof is charged in a compacting mold. The powder mixture in a cavity is orientated in a magnetic field. It is compressed and Joule heated. Thus, the powder mixture is fixed. When the powder mixture is fixed into a magnet, the ratio (Po/Lo) of the average grain size Po of the anisotropic magnet powder to the size of the magnet Lo which size is measured in the orientation direction is preferably 0.6 or more.Type: GrantFiled: November 28, 1995Date of Patent: April 29, 1997Assignee: Matsushita Electric Industrial Co., Ltd.Inventor: Fumitoshi Yamashita
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Patent number: 5609695Abstract: Homogenizing heat-treatment is conducted for changing an ingot containing R (R: Sm or a substance obtained by replacing a part of Sm with one or more kinds of rare earth elements) and T (T: Fe or a substance obtained by replacing a part of Fe with one or more kinds of transition elements) as main component into an alloy ingot mainly containing a R.sub.2 T.sub.17 phase. Next, the above-described alloy ingot is allowed to absorb hydrogen in hydrogen gas in the temperature range of 70.degree. C. to 300.degree. C., and at pressures of 5 kgf/cm.sup.2 or more, thus conducting coarse crushing treatment.Type: GrantFiled: December 20, 1994Date of Patent: March 11, 1997Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kiyoshi Kojima, Takeshi Takahashi
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Patent number: 5601662Abstract: There is disclosed a method of introducing magnetic anisotropy into a magnetic material, in which a laser beam is selectively radiated on the surface of a magnetic material to locally heat it, thereby forming a pattern of boundary phases for magnetically dividing a main phase of the magnetic material into a plurality of regions, and magnetic domains of the divided main phase regions are controlled to induce magnetic anisotropy in the main phase regions.Type: GrantFiled: June 29, 1990Date of Patent: February 11, 1997Assignee: Kabushiki Kaisha ToshibaInventors: Takahiro Hirai, Tadahiko Kobayashi, Masashi Sahashi
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Patent number: 5602527Abstract: An assembly of a dry coating (A) that has a magnetic powder with a saturation flux density of at least 100 emu/g is dispersed in a binder. A magnetostrictive metal (B), when the coating (A) is magnetized, resonates mechanically at a predetermined frequency in the range of varying frequencies. The varying frequencies are generated from an applied alternating magnetic field. Changes in flux density and permeability are experienced. When the coating (A) is not magnetized, metal (B) does not resonate at the predetermined frequency, thus experiencing no changes in flux density or permeability. The dry coating (A) and the metal (B) have a superposed relationship in such a way that the latter is capable of mechanical resonance, the marker being so adapted that when said coating (A) is magnetized, the predetermined frequency at which the flux density or permeability will change is generated as a signal in response to the applied alternating magnetic field.Type: GrantFiled: February 23, 1995Date of Patent: February 11, 1997Assignee: Dainippon Ink & Chemicals IncorporatedInventor: Wataru Suenaga
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Patent number: 5595608Abstract: A permanent magnet which contains R, T and B as main ingredients wherein R is Y or a rare earth element and T is Fe or Fe and Co and has a primary phase of R.sub.2 T.sub.14 B is produced by compacting a mixture of 60 to 95 wt % of a primary phase-forming master alloy and a grain boundary phase-forming master alloy both in powder form and sintering the compact. The primary phase-forming master alloy has columnar crystal grains of R.sub.2 T.sub.14 B with a mean grain size of 3-50 .mu.m and grain boundaries of an R rich phase and contains 26-32 wt % of R. The grain boundary phase-forming master alloy is a crystalline alloy consisting essentially of 32-60 wt % of R and the balance of Co or Co and Fe. In anther form, a permanent magnet which contains R, T and B as main ingredients wherein R is yttrium or a rare earth element, T is Fe or Fe+Co/Ni and has a primary phase of R.sub.2 T.sub.Type: GrantFiled: November 2, 1994Date of Patent: January 21, 1997Assignee: TDK CorporationInventors: Katashi Takebuchi, Shinya Fujito, Shinya Hashimoto, Koichi Yajima
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Patent number: 5573603Abstract: A method of making a solid magnetic material from Sm.sub.2 Fe.sub.17 N.sub.3-x type intermetallic nitride powder, where 0.ltoreq.x.ltoreq.1, comprises the following steps:a--the powder is mixed intimately with glass powder having a conversion temperature Tg between 260.degree. C. and 310.degree. C. and a softening temperature Tf less than 400.degree. C., the proportion of glass powder being between 10% and 30% of the total volume;b--the mixture is compressed to obtain a solid;c--the solid obtained is subjected in a neutral gas atmosphere to a heat cycle during which a temperature not less than Tf+5.degree. C. and not more than 420.degree. C. is maintained for at least one hour.Type: GrantFiled: March 1, 1995Date of Patent: November 12, 1996Assignee: Alcatel Alsthom Compagnie Generale d'ElectriciteInventors: Philippe Mocaer, Patrick Dubots, Christian Belouet
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Patent number: 5562782Abstract: The present invention aims at providing a powdery raw material composition for a permanent magnet superior in the magnetic properties and easy in preparation, a magnetically anisotropic permanent magnet, and a method for producing the magnet by use of the powdery raw material composition. A powdery raw material composition for a permanent magnet according to the present invention is one prepared by subjecting a mixture composed of 13-18 weight % of a neodymium powder, 4-10 weight % of a boron powder and the rest of an acicular iron powder coated with aluminum phosphate to a temperature above 600.degree. C. in an atmosphere initially of a hydrogen-containing reducing gas followed later by an inert gas, and a magnetically anisotropic permanent magnet is prepared by compression molding a mixture obtained from the powdery composition and a binder under heating in the presence of a magnetic field.Type: GrantFiled: May 5, 1995Date of Patent: October 8, 1996Assignees: Kawasaki Teitoku Co., Ltd., Komeya Inc., Sanei Kasei Co., Ltd.Inventor: Yasunori Takahashi
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Patent number: 5492754Abstract: Disclosed is an absorbent composition including a hydrogel-forming polymeric material and a magnetically-responsive material; disposable absorbent products, including the absorbent composition, intended for the absorption of body fluids; and a method for incorporating the absorbent composition into disposable absorbent products.Type: GrantFiled: December 15, 1993Date of Patent: February 20, 1996Assignee: Kimberly-Clark CorporationInventor: Franklin M. C. Chen
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Patent number: 5492572Abstract: A magnetized or unmagnetized body of a permanent magnet material is heated in a pattern by a laser beam to a temperature sufficient to lower the coercivity of selected heated regions of the pattern and exposed to a magnetic field to magnetize or to remagnetize the selected heated regions. A pattern guide is used in the process to densify the pattern. In the process, energy is directed through the pattern guide and onto the selected regions, while the pattern guide prevents or minimizes heating of unselected portions of the body. Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength.Type: GrantFiled: November 25, 1994Date of Patent: February 20, 1996Assignee: General Motors CorporationInventors: Thaddeus Schroeder, John R. Bradley, Thomas A. Perry, Bruno P. B. Lequesne
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Patent number: 5492571Abstract: An article comprising first and second bodies of permanent magnet material, each of said first and second bodies consisting substantially of a substrate of permanent magnet material being magnetized substantially uniformly to a predetermined flux density in a range from zero flux to 100% flux saturation of the permanent magnet material; each of the first and second bodies also comprising a pattern of at least one affected volume in a surface of the body, wherein each affected volume has a magnetic flux density that varies from the substantially uniform predetermined flux density and wherein the first and second bodies are stacked and fixedly attached so that the pattern on each body aligns with the pattern on the other body, wherein at least one affected volume on the first body is aligned with at least one affected volume on the second body and wherein the aligned affected volumes comprise a pole detectable by a magnetic sensor.Type: GrantFiled: October 25, 1993Date of Patent: February 20, 1996Assignee: General Motors CorporationInventors: Robert A. Frosch, Thomas A. Perry, John R. Bradley, Thaddeus Schroeder, Bruno P. B. Lequesne
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Patent number: 5489343Abstract: An R-Fe-B-based, sintered magnet, wherein R is one or more of rare earth elements including Y, is produced by the method including the steps of mixing fine R-Fe-B-based magnet powder with a mineral oil and/or a synthetic oil having a fractional distillation temperature range of 150.degree.-400.degree. C. and a kinetic viscosity of 10 cSt or less to prepare a mixture; charging the mixture under pressure into a die cavity equipped with a filter, to which an orientated magnetic field is applied, while removing a mineral oil and/or a synthetic oil from the mixture; compressing the mixture in the die cavity to carry out a wet molding while orientating the powder to prepare a green body; heating the green body to a temperature up to 500.degree. C. at a speed of 10.degree. C./min or less under pressure of 10.sup.-1 Torr or less for 30 minutes or more to remove a mineral oil and/or a synthetic oil from the green body; and then sintering the green body.Type: GrantFiled: January 27, 1994Date of Patent: February 6, 1996Assignee: Hitachi Metals, Ltd.Inventors: Kimio Uchida, Masahiro Takahashi, Masamichi Ozaki, Akira Kikuchi
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Patent number: 5478409Abstract: It is an object of the present invention to provide a method of producing sintered- or bond- rare earth element.iron.boron magnets obtainable easily and superior in magnetic properties with stable performance. The method of producing sintered rare earth element.iron.boron magnets according to the present invention is characterized by that it comprises steps of mixing in a scheduled ratio an acicular iron powder coated with a coating material, a rare earth element powder coated with a coating material and a boron powder coated with a coating material, and subjecting the mixture to compression molding followed by sintering of the molded mixture in the presence of a magnetic field. The method of producing bond rare earth element.iron.Type: GrantFiled: October 13, 1994Date of Patent: December 26, 1995Assignees: Kawasaki Teitoku Co., Ltd., Komeya Inc., Sanei Kasei Co., Ltd.Inventor: Yasunori Takahashi
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Patent number: 5435859Abstract: A method of producing a rare earth anisotropic bond magnet comprising the steps of:melting an aloy composed of 10-30 atom % of R (wherein R designates at least one rare earth element including yttrium), 2-28 atom % of boron and 65-82 atom % of M (wherein M designates at least one of iron, cobalt and nickel) and rapidly cooling the melted alloy to produce powder material,subjecting the material to stamping at the temperature of 300.degree.-900.degree. C. in an inert gas atmosphere to pulverize and press the material to a scaly shape andcooling the pulverized material so that a magnetic anisotropy is produced in the vertical direction relative to the pressed surface.Type: GrantFiled: August 4, 1993Date of Patent: July 25, 1995Assignee: ERD CorporationInventors: Michihiro Torii, Masanao Okuda, Yoshikazu Ikeda
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Patent number: 5425818Abstract: A densified high performance rare earth-iron-nitrogen permanent magnet obtained from a powder of a Th.sub.2 Zn.sub.17 compound containing nitrogen at interlattice sites, without using autogeneous sintering and yet preventing decomposition and/or denitrification from occurring. The process for producing the same need not necessarily use a binder, and it comprises compaction molding, or charging while applying a magnetic field, a powder of a nitrogen intrusion T--R--N compound having a specified composition and a Th.sub.2 Zn.sub.17 crystal structure, and applying thereto shock compression at a drive pressure of from 10 to 25 GPa as reduced to an equivalent drive pressure in an iron capsule.Type: GrantFiled: November 29, 1993Date of Patent: June 20, 1995Assignee: Sumitomo Special Metals Co., Ltd.Inventors: Satoshi Hirosawa, Takashi Ikegami, Ken Makita, Tsutomu Mashimo
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Patent number: 5416457Abstract: A lateral orientation type of anisotropic permanent magnet having a face of magnetic application and at least one lateral face adjacent to the face of magnetic application. An axis of easy magnetization of particles of a magnetic powder constituting the permanent magnet is oriented substantially along lines from the lateral face toward the face of magnetic application to increase the peak value of the surface magnetic flux density at the face of magnetic application.Type: GrantFiled: August 10, 1994Date of Patent: May 16, 1995Assignee: Kawasaki Steel CorporationInventors: Satoshi Nakatsuka, Akira Yasuda, Itsuo Tanaka, Koichi Nushiro, Takahiro Kikuchi
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Patent number: 5405455Abstract: Disclosed is a novel method for the preparation of a rare earth-based permanent magnet by the so-called two-alloy process in which powders of two kinds of rare earth-containing magnetic alloys each having a different composition from the other are blended together in a specified proportion and the powder blend is shaped in a magnetic field into a green body which is sintered. In the invention, the first magnetic alloy has a composition of the formula R.sub.2 T.sub.14 B, in which R is a rare earth element selected from the group consisting of neodymium, praseodymium, dysprosium and terbium and T is iron or a combination of iron and cobalt, while the second alloy has a composition of the formula R.sub.a Fe.sub.b Co.sub.c B.sub.d M.sub.Type: GrantFiled: September 13, 1993Date of Patent: April 11, 1995Assignee: Shin-Etsu Chemical Co. Ltd.Inventors: Matou Kusunoki, Takehisa Minowa, Masao Yoshikawa
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Patent number: 5399311Abstract: A magnet is formed as a ring magnet and magnetized by radial application of a magnetic field while the intensity of the magnetic field is changed periodically along the circumference of the ring magnet to give a circumferentially sinusoidal waveform distribution of magnetic flux density to the ring magnet in the magnetized state of the magnet.Type: GrantFiled: November 12, 1992Date of Patent: March 21, 1995Assignee: Daido Tokushuko Kabushiki KaishaInventors: Yasuaki Kasai, Hiyoshi Yamada, Norio Yoshikawa
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Patent number: 5366566Abstract: A method for preparing a sample of a magnetic susceptibility compound .chi. comprises the steps of providing a vertical magnetic induction B which has a magnetic induction gradient dB/dz and which is such that B.dB/dz has a sign opposite to that to the weight of the sample and such that the magnetic force (.chi..B.dB/dz)/.sub..mu.0 is higher than the weight and heating at a temperature close to the melting temperature.Type: GrantFiled: July 31, 1991Date of Patent: November 22, 1994Assignee: Centre National de la Recherche ScientifiqueInventor: Robert Tournier
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Patent number: 5338372Abstract: Anisotropic rare-earth permanent magnets characterized in that an aggregate of a plurality of blocks, to each of which anisotropy is imparted, is formed using powders of magnetic material containing rare-earth elements, and the adjoining blocks are powder-metallurgically bonded together under pressure into one piece; a method of making anisotropic rare-earth permanent magnets by molding anisotropic blocks by magnetic-field molding, arranging, aggregating and sealing a plurality of blocks in a bag, and cold hydrostatic pressing the aggregate of blocks in the absence of magnetic field; and a suitable metal mold for magnetic-field molding anisotropic permanent magnets of a relatively large size.Type: GrantFiled: December 3, 1992Date of Patent: August 16, 1994Assignee: Hitachi Metals, Ltd.Inventor: Kazunori Tabaru
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Patent number: 5288454Abstract: A method for controlling the remanance of a sintered magnet by varying the time when the orienting field is applied during cold compression. The method comprises obtaining powders of an appropriate particle size, compressing the powders in an oriented field, sintering, heat treating, machining and magnetizing to technical saturation. The cold compressing in an orienting field takes place at a precompression rate of more than 15% before the orienting field is applied. The method applies to magnets of all shapes which must have magnetic induction well defined in modulus and in direction, particularly annular magnets for traveling wave tubes.Type: GrantFiled: January 6, 1993Date of Patent: February 22, 1994Assignee: Aimants Ugimag S.A.Inventors: Jean-Marc Lang, Robert Tissot
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Patent number: 5283130Abstract: A permanent magnet is heated in a pattern by a laser beam to a localized temperature above the Curie point or a temperature sufficient to reduce the magnet coercivity sufficiently for the field of the magnet or an external field to remagnetize the pattern in the reverse direction. Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength.Type: GrantFiled: November 6, 1991Date of Patent: February 1, 1994Assignee: General Motors CorporationInventors: John R. Bradley, Thomas A. Perry, Thaddeus Schroeder
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Patent number: 5275688Abstract: A monocrystal of a R-T intermetallic compound containing R (at least one lanthanide element inclusive of Y) and T (at least one transition metal element such as Fe, Co, Ni, Cr and Mn) is grown by a solid phase method. First a precursor in which a primary phase of the intermetallic compound and a low-melting eutectic crystal phase exist is prepared. The precursor is successively heated from one end to another end while it is often contacted at one end with a seed crystal. Then the low-melting eutectic crystal phase functions as a flux intergranular substance to ensure the consistent manufacture of a monocrystal aligned with the crystallographic orientation of the seed crystal or at the start-of-heating point.Type: GrantFiled: May 19, 1992Date of Patent: January 4, 1994Assignee: TDK CorporationInventors: Teruo Mori, Shigeo Okamoto, Kazunori Hirose
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Patent number: 5236518Abstract: A means is provided for improving the magnetic permeability of a magnetic circuit within a variable reluctance sensor having off-set, permanent magnets by appropriately annealing the magnetic flux member. The annealing process includes heating the machined magnetic flux member in a vacuum to a temperature and for a duration sufficient to austenitize the magnetic steel so that full carbide solution is obtained, for example about 1300.degree. F. to about 1550.degree. F. for a duration of about 15 to 30 minutes. The magnetic flux member is then appropriately cooled in the vacuum so as to prevent the formation of martensite. The magnetic circuit, incorporating the annealed magnetic flux member, exhibited improved magnetic permeability, and the sensor signal was increased by as much as about 60 percent during operation.Type: GrantFiled: February 14, 1992Date of Patent: August 17, 1993Assignee: General Motors CorporationInventors: Takeshi Shirai, Andrzej M. Pawlak, Donald L. Richardson
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Patent number: 5217541Abstract: A permanent magnet essentially consisting of in weight percent, 60% to 68% at least one transition element by weight, 30% to 38% at least one rare earth element by weight, 0.1% to 1.5% nitrogen by weight, and 0.8% to 1.5% boron by weight is disclosed. A method for producing the permanent magnet containing at least one rear element, at least one rare earth element, nitrogen and boron includes melting, cooling, milling, magnetizing, and compacting the transition element, the rare earth element and boron to form a green compact, and then sintering the green compact in nitrogen atmosphere having a constant partial pressure for 1 to several hours to form the permanent magnet.Type: GrantFiled: August 26, 1991Date of Patent: June 8, 1993Assignee: High End Metals Corp.Inventors: Tsung-Shune Chin, Shiang-Jiun Heh, Ken-Der Lin
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Patent number: 5201962Abstract: A method of manufacturing a permanent magnet which comprises applying one directional pressure and an electric current to an aggregate through a pair of electrodes to cause the aggregate to undergo a plastic deformation thereby to expand an axially projected surface area. The aggregate used is of a type containing alloy flakes interlocked with each other. The alloy flakes are those made of at least one rare earth metal and a ferrous component by the use of a melt quenching process.Type: GrantFiled: July 11, 1990Date of Patent: April 13, 1993Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Fumitoshi Yamashita, Masami Wada
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Patent number: 5181971Abstract: This specification discloses a method of manufacturing a magnet roller having the step of disposing a plurality of pairs of magnetic poles each comprising the starting magnetic pole and terminal magnetic pole of a magnetic line of force on the peripheral surface of a cavity in a metal mold in which a resin magnet is molded and oriented so that straight lines passing through the starting magnetic poles and terminal magnetic poles of the pairs of magnetic poles are substantially on the same plane and extend through the cavity substantially in parallelism to one another, molding and orienting a resin magnet material poured into the cavity while applying a plurality of magnetic lines of force for orientation into the cavity in the same direction, thereby obtaining a molded article having at least four magnetic peaks, and the steps of inverting part of the magnetic properties of the magnetic peaks of the molded article so that the magnetic properties of the adjacent magnetic peaks differ from each other.Type: GrantFiled: January 22, 1990Date of Patent: January 26, 1993Assignee: Canon Kabushiki KaishaInventor: Naoji Ohtsuka
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Patent number: 5143560Abstract: A method for the high volume manufacture of Fe-B-R-T alloy powders without sacrificing the resultant magnetic properties (such as intrinsic magnetic coercivity) of the alloy involves hydrogen decrepitation of vacuum cast or die-upset billets of the alloy. Hydriding is carried out at a partial pressure of hydrogen of between 250 and 760 mm Hg at 100.degree. to 500.degree. C. for 30 minutes to 6 hours or longer, depending upon load size. Dehydriding occurs in a vacuum below 10.sup.-2 mm Hg or in an inert atmosphere possessing a partial pressure of hydrogen below 10.sup.-2 mm Hg. The alloy powder is preferably incorporated in matrix or composite magnets by the addition of a binder prior to pressing and orienting. The binder may set during pressing in a hot die, or by heating after pressing in a cold die.Type: GrantFiled: April 20, 1990Date of Patent: September 1, 1992Assignee: Hitachi Metals, Inc., Ltd.Inventor: Manfred Doser
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Patent number: 5137588Abstract: Magnet material of the Sm-Fe-N system having a crystalline, hard magentic phase with a Th.sub.2 Zn.sub.17 crystal structure, wherein N atoms are incorporated into the crystal lattice, is produced. First a preliminary product is formed by sintering a Sm-Fe powder which is oriented in a magnetic field to provide a sintered body having a two-component Sm-Fe phase. The sintered body is heat treated in a nitrogen atmosphere to form the Sm-Fe-N hard magnetic phase. The nitrogen atomosphere may advantageously be reactive nitrogen.Type: GrantFiled: July 25, 1991Date of Patent: August 11, 1992Assignee: Siemens AktiengesellschaftInventors: Joachim Wecker, Ludwig Schultz, Matthias Katter, Kurt Schnitzke
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Patent number: 5137587Abstract: A shaped body of anisotropic magnetic material based on the Sm-Fe-N system which has a crystalline, hard magnetic phase with a Th.sub.2 Zn.sub.17 crystal structure, wherein N atoms are incorporated in the crystal lattice, is produced by compacting a powder Sm-Fe preliminary product with an Sm-Fe phase having a magnetically isotropic structure, followed by hot-shaping to provide an intermediate product with a Sm-Fe phase having a magnetically anisotropic structure, followed by heat treating the intermediate product in a nitrogen atmosphere to provide a Sm-Fe-N hard magnetic phase.Type: GrantFiled: July 25, 1991Date of Patent: August 11, 1992Assignee: Siemens AktiengesellschaftInventors: Ludwig Schultz, Kurt Schnitzke, Joachim Wecker, Matthias Katter
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Patent number: 5123974Abstract: In one embodiment this invention provides a process for decreasing the resistivity of an electrical conductor.The process involves the application of high temperature and an external field to a conductor to induce a current flow and physicochemical transition in the conducting matrix.Type: GrantFiled: April 30, 1991Date of Patent: June 23, 1992Inventor: Dominic J. Giancola
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Patent number: 5098619Abstract: An improved process for forming high quality ferrite magnets utilizes relatively coarsely ground magnetic materials. The process includes pre-milling a blended and calcined magnetic material to about 0.7-1.2 microns, pressing the blend into a preform shape in the presence of an orienting magnetic field, granulating the preformed material, pre-sintering the granules short of complete sintering, milling the granules to a coarse size of about 1-2 microns, forming the milled blend into desired forms in the presence of an orienting magnetic field, sintering the pressed material, and optionally machining the sintered material.Type: GrantFiled: October 2, 1989Date of Patent: March 24, 1992Assignee: Hitachi Metals International, Ltd.Inventor: George Facaros
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Method and particle mixture for making rare earth element, iron and boron permanent sintered magnets
Patent number: 5091020Abstract: A method for making rare earth element, iron and boron sintered permanent magnets, and a particle mixture for use therein. A hydrided 100% dross or particle mixture of virgin alloy particles and scrap alloy particles and/or dross alloy particles are dehydrided and sintered to produce a substantially fully dense article for use as a permanent magnet.Type: GrantFiled: November 20, 1990Date of Patent: February 25, 1992Assignee: Crucible Materials CorporationInventor: Andrew S. Kim -
Patent number: 5091021Abstract: Nonmagnetized permanent magnet material is heated in a pattern by a laser beam to a localized temperature above the Curie point or a temperature sufficient to reduce the coercivity sufficiently for an external field to magnetize the pattern in the direction of the field. Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength. Alternating pole magnets of this type can be used for stepper motor magnets.Type: GrantFiled: September 28, 1990Date of Patent: February 25, 1992Assignee: General Motors CorporationInventors: Thomas A. Perry, John R. Bradley, Thaddeus Schroeder, Carlton D. Fuerst
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Patent number: 5089060Abstract: A permanent magnet is heated in a pattern by a laser beam to a localized temperature above the Curie point or a temperature sufficient to reduce the magnet coercivity sufficiently for the field of the magnet or an external field to remagnetize the pattern in the reverse direction. Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength.Type: GrantFiled: September 28, 1990Date of Patent: February 18, 1992Assignee: General Motors CorporationInventors: John R. Bradley, Thomas A. Perry, Thaddeus Schroeder
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Patent number: 5087302Abstract: A process for producing a rare earth magnet of magnetically improved performance wherein a specific titanate coupling agent is added in one step of the process to enhance the oxidation resistance of the raw materials during production and a special degassing step is incorporated to allow for the removal of the residual titanate coupling agent. The resultant rare earth magnet exhibits improved maximum magnetic energy product ((BH).sub.max) and magnetic coercive force (H.sub.c) as well as other magnetic properties. Rare earth magnet produced by the process is also disclosed.Type: GrantFiled: January 18, 1991Date of Patent: February 11, 1992Assignee: Industrial Technology Research InstituteInventors: Cheng H. Lin, Shi K. Chen, Ying C. Hung, Wen S. Ko, Wen C. Chang
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Patent number: 5080731Abstract: A highly oriented rare earth based permanent magnet satisfies the relationship a.gtoreq.b>c where a is the longer side or major axis of the magnet, b is the shorter or minor axis of the magnet, and c is the thickness of the magnet, and that has a flat shape which is magnetized in the direction of thickness c, with the direction of magnetization being inclined at an angle of no more than 3 degrees with respect to the line normal to the plane defined by a and b. The magnet is produced by loading an alloy powder as the starting material into a mold having a cavity that satisfies the relationship A.gtoreq.B>C where A is the longer side or major axis of the cavity, B is the shorter side or minor axis of the cavity, and C is the depth of the cavity; exerting a compressive force of at least 0.4 tons/cm.sup.Type: GrantFiled: August 15, 1989Date of Patent: January 14, 1992Assignee: Hitachi Metals, Ltd.Inventors: Kazunori Tabaru, Motoharu Shimizu
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Patent number: 5079534Abstract: An apparatus for magnetizing a permanent magnet which includes a frame including first and second relatively movable members arranged to form a core frame which supports first and second conic co-axial poles enclosed by the movable frame members for creating a magnetic flux circuit with an adjustable air gap for enclosing a product to be magnetized. The apparatus is energized by coils wound about the poles and enclosing the air gap. The poles include a bore co-axially aligned with the co-axial axis of the poles and a press ram dimensioned to move within the bore.Type: GrantFiled: September 18, 1990Date of Patent: January 7, 1992Inventors: Erich Steingroever, Dietrich Steingroever
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Patent number: 5015306Abstract: Permanent magnets are prepared by a method comprising mixing a particulate rare earth-iron-boron alloy with a particulate transition metal, aligning the magnetic domains of the mixture, compacting the aligned mixture to form a shape, and sintering the compacted shape.Type: GrantFiled: October 30, 1989Date of Patent: May 14, 1991Assignee: Union Oil Company of CaliforniaInventor: Mohammad H. Ghandehari
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Patent number: 5013411Abstract: Corrosion-resistant rare earth magnets and a method for their manufacture, said magnets containing at least one rare earth element in an amount of 5 to 40 weight %, Fe in an amount of 50 to 90 weight %, Co in an amount of 0 to 15 wt %, B in an amount of 0.2 to 8 weight %, and at least one additive selected from Ni, Nb, Al, Ti, Zr, Cr, V, Mn, Mo, Si, Sn, Ga, Cu, and Zn in an amount of 0 to 8 weight %. The method comprises the steps of: (i) pretreating the surfaces of the magnet after sintering it; (ii) activating the surfaces thereof; and (iii) coating the surfaces thereof with at least one layer of Ni-containing film by electroplating. The activating may be carried out by treating the surfaces with a soap or a surface active agent. The activated surfaces may be subjected to ultrasonic vibrations in water to remove foreign substances before electroplating.Type: GrantFiled: May 31, 1989Date of Patent: May 7, 1991Assignee: Shin-Etsu Chemical Co., Ltd.Inventors: Takehisa Minowa, Masao Yoshikawa
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Patent number: 5009706Abstract: Rare-earth alloy anisotropic powders consist of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one on neodymium and praseodymium or at least one of them and or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists of iron and unavoidable impurities. Up to 20 percent of the iron contained is replaceable with cobalt. The alloy powders are made up of flat crystal grains having mean thickness h (the shortest measure), d not smaller than 0.01 .mu.m and not larger than 0.5 .mu.m and ratio d/h not smaller than 2, where d is the means measure of the grains taken at right angles to the widthwide direction thereof, and the alloy powders are magnetically anisotropic.Type: GrantFiled: July 18, 1990Date of Patent: April 23, 1991Assignee: Nippon Steel CorporationInventors: Hiroaki Sakamoto, Masahiro Fujikura, Toshio Mukai
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Patent number: 5007972Abstract: A process for fabricating high strength Sm.sub.2 TM.sub.17 (TM=transition metal) magnets is disclosed. An alloy is crushed and pulverized to a very fine powder. The powder is aligned in a magnetic field, cold pressed to substantially immobilize the powder particles and then compacted by hot isostatic pressing. The material is either homogenized at this time or prior to crushing. Thereafter, the powder is optimized by an aging heat treatment which includes isothermal exposure followed by controlled cooling. When aging is complete, the compact is magnetized.Type: GrantFiled: June 9, 1988Date of Patent: April 16, 1991Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Kaplesh Kumar, Herbert A. Newborn
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Patent number: 5004580Abstract: A method and apparatus for packing a permanent magnet powder wherein a solenoid coil is provided near the opening of a cylindrical molding space of a mold in such a manner that the direction of the central axis of the solenoid coil substantially coincides with the central axis of the molding space, and an alternating current magnetic field is applied, so that a permanent magnet powder above the opening is packed into the molding space. A magnetic pole may be provided in the center of the solenoid coil. The method of the present invention can be applied to not only a powder for a sintered magnet but also a powder for a bonded magnet.Type: GrantFiled: April 13, 1990Date of Patent: April 2, 1991Assignee: Fuji Electrochemical Co. Ltd.Inventors: Yoshio Matsuo, Hirofumi Nakano, Masakuni Kamiya, Kezuo Matsui
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Patent number: RE34322Abstract: A method of preparing alloy of a transition metal and lanthanide comprising the steps of alloying a transition metal, boron, at least one lower-weight lanthanide having none or few stable compounds with iron, optionally one or more higher-weight lanthanides, a glass former, and optionally the pseudo lanthanide, yttrium; forming an amorphous or nearly amorphous metastable microstructure in the alloy; and heating the amorphous alloy to form a polycrystalline, multiphase, fine-grain single-domain structure.Type: GrantFiled: January 31, 1989Date of Patent: July 27, 1993Assignee: The United States of America as represented by the Secretary of the NavyInventor: Norman C. Koon