Patents by Inventor Takuo Takeshita

Takuo Takeshita has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5587024
    Abstract: A solid resin-coated composite magnet powder for producing an improved anisotropic bonded magnet contains individual anisotropic magnet powder particles each having a surface coated with a solid resin layer thereon. A method is disclosed for producing a solid resin-coated magnet powder, including the steps of kneading an anisotropic magnet powder with a solid resin under a reduced pressure, granulating the resultant mixture to produce a solid resin-coated composite magnet powder, and milling the composite magnet powder produced to separate the solid resin-coated composite magnet powder into individual anisotropic magnet powder particles coated with the solid resin.
    Type: Grant
    Filed: April 17, 1995
    Date of Patent: December 24, 1996
    Assignee: Mitsubishi Materials Corporation
    Inventors: Ryoji Nakayama, Takuo Takeshita, Muneaki Watanabe
  • Patent number: 5543070
    Abstract: This invention relates to a magnetic recording powder having a low Curie temperature and a high saturation magnetization (.sigma.s). The magnetic recording powder of this invention is of a composite oxide having a hexagonal ferrite type crystal structure comprises: (a) between 14 and 20 atomic % of at least one of strontium oxide and barium oxide, (b) between 15 and 40 atomic % of chromium oxide, (c) between 2 and 15 atomic % of at least one member of the group consisting of zinc oxide, magnesium oxide and copper oxide, (d) between 2 and 15 atomic % of at least one member of the group consisting of titanium oxide, zirconium oxide and tin oxide, with substantial remainder being iron oxide and unavoidable impurities. Further, the magnetic recording powder of this invention is of a composite oxide having saturation magnetization (.sigma.s) of 15 emu/g or higher, and a Curie temperature (Tc) of 155.degree. C. or lower.
    Type: Grant
    Filed: December 1, 1994
    Date of Patent: August 6, 1996
    Assignee: Mitsubishi Materials Corporation
    Inventors: Kouichi Ishiyama, Kazunori Igarashi, Norikazu Komada, Takuo Takeshita, Kiyoyuki Ookubo
  • Patent number: 5505794
    Abstract: The present invention presents a method and an apparatus for heat treating a metallic material by performing hydrogen absorption in or desorption from the metallic material. The method includes the steps of recovering the hydrogen gas released from a desorption step and recycling it to a hydrogen absorbing step. Hydrogen recovering can be performed either in a device containing a hydrogen absorbing alloy or in a second heat treating furnace containing the metallic material. Various controlling devices are used to regulate the process of heat treating and recovering of hydrogen gas.
    Type: Grant
    Filed: May 19, 1994
    Date of Patent: April 9, 1996
    Assignee: Mitsubishi Materials Corporation
    Inventors: Ryoji Nakayama, Takuo Takeshita, Shouichi Kubo
  • Patent number: 5486239
    Abstract: A magnetically anisotropic R-T-B-M powder material which is starting with an R-T-B-M raw alloy material having a c-axis crystal orientation of an R.sub.2 T.sub.14 B-type intermetallic compound phase. In one embodiment, the starting material is compressed sintered in a magnetic field and recompressed in a magnetic field. In a second embodiment, the starting material is hot-pressed and homogenized. A method of manufacturing anisotropic magnets such as bond and full density magnets made from the magnetically anisotropic R-T-B-M powder material is disclosed.
    Type: Grant
    Filed: October 29, 1993
    Date of Patent: January 23, 1996
    Assignee: Mitsubishi Materials Corporation
    Inventors: Ryoji Nakayama, Takuo Takeshita, Yoshinari Ishill
  • Patent number: 5417773
    Abstract: The present invention provides a method for producing a rare earth alloy magnet powder exhibiting stable and superior magnetic properties using hydrogenation followed by dehydrogenation. In a method for producing a rare earth alloy magnet powder wherein a homogenized rare earth alloy magnet alloy material is subjected to hydrogenation at a temperature in a range between 750.degree. C. and 950.degree. C., followed by dehydrogenation at a temperature in a range between 750.degree. C. and 950.degree. C.; cooled; and crushed, both the hydrogenation and the dehydrogenation are carried out in a vacuum tube furnace; and the alloy material in the dehydrogenation step maintains a temperature drop of at most 50.degree. C. due to an endothermic reaction which occurs during the dehydrogenation step.
    Type: Grant
    Filed: October 6, 1994
    Date of Patent: May 23, 1995
    Assignee: Mitsubishi Materials Corporation
    Inventors: Ryoji Nakayama, Takuo Takeshita, Yoshinari Ishii, Tamotsu Ogawa
  • Patent number: 5395462
    Abstract: A hot press molded body or an HIP molded body having one of a composition comprisingR: 10-20 atomic %, B: 3-20 atomic %, anda total amount of one or a plurality of Ga, Zr, and Hf: 0.001-5.0 atomic %,a remainder comprising Fe and unavoidable impurities; ora composition comprisingR: 10-20 atomic %, B: 3-20 atomic %, anda total amount of one or a plurality of Ti, V, Nb, Ta, Al, and Si: 0.001-5.0 atomic %,a remainder comprising Fe and unavoidable impurities; ora composition comprising Co: 0.1-50 atomic % added to one of the above compositions, havingan aggregate structure of crystallized grains having as a main phase thereof a R.sub.2 Fe.sub.14 B type or R.sub.2 (Fe, Co).sub.14 B type intermetallic compound having a tetragonal structure, the crystallized grains having dimensions of 0.05-20 .mu.
    Type: Grant
    Filed: February 23, 1993
    Date of Patent: March 7, 1995
    Assignee: Mitsubishi Materials Corporation
    Inventors: Takuo Takeshita, Ryoji Nakayama, Tamotsu Ogawa
  • Patent number: 5372657
    Abstract: Disclosed herein is an amorphous material in the form of foil for the regenerator, which is prepared by quenching a melt of a rare earth alloy by injection toward the surface of a roll running at a high speed, said alloy being composed of one or more rare earth elements in an amount of 50-99 atomic %, with the remainder being one or more iron family elements. This amorphous material has a large, stable specific heat capacity at very low temperatures.
    Type: Grant
    Filed: September 11, 1992
    Date of Patent: December 13, 1994
    Assignees: Mitsubishi Materials Corp., Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasuhiro Hanaue, Etsuji Kimura, Takuo Takeshita, Uichiro Mizutani, Yoshiki Hoshino
  • Patent number: 5360784
    Abstract: An oxide superconducting material is coated with silver or an alloy thereof and shaped into a linear body, and the linear body is subjected to diameter reduction by means of groove roll rolling, a swaging machine and the like, and then differential speed rolling and heat treatment are repeatedly performed, whereby the linear body is shaped into a tape-shaped wire material. The microstructure control in the longitudinal direction is performed uniformly and efficiently, and a superconducting wire having a high c-axis orientation ratio and a large critical current density Jc at a service temperature is obtained.
    Type: Grant
    Filed: July 31, 1992
    Date of Patent: November 1, 1994
    Assignee: Mitsubishi Materials Corporation
    Inventors: Toshio Kimura, Takuo Takeshita, Motokazu Suzuki
  • Patent number: 5354040
    Abstract: The present invention presents a method and an apparatus for heat treating a metallic material by performing hydrogen absorption in or desorption from the metallic material. The method includes the steps of recovering the hydrogen gas released from a desorption step and recycling it to a hydrogen absorbing step. Hydrogen recovering can be performed either in a device containing a hydrogen absorbing alloy or in a second heat treating furnace containing the metallic material. Various controlling devices are used to regulate the process of heat treating and recovering of hydrogen gas.
    Type: Grant
    Filed: November 25, 1992
    Date of Patent: October 11, 1994
    Assignee: Mitsubishi Materials Corporation
    Inventors: Ryoji Nakayama, Takuo Takeshita, Shouichi Kubo
  • Patent number: 5338371
    Abstract: There is disclosed a R--Fe--B or R--Fe--Co--B alloy permanent magnet powder which may contain Ga, Zr or Hf, or may further contain Al, Si or V. Each individual particle of the powder includes a structure of recrystallized grains containing a R.sub.2 Fe.sub.14 B or R.sub.2 (Fe,Co).sub.14 B intermetallic compound phase. The intermetallic compound phase has recrystallized grains of a tetragonal crystal structure having an average crystal grain size of 0.05 to 20 .mu.m. At least 50% by volume of the recrystallized grains of the aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain. In order to manufacture the magnet powder, regenerative material and alloy material are prepared and their temperature is elevated in a hydrogen atmosphere. Then, the alloy material and the regenerative material are held in the same atmosphere at a temperature or 750.degree. C. to 950.degree. C., and then held in a vacuum at 750.degree. C.
    Type: Grant
    Filed: November 19, 1992
    Date of Patent: August 16, 1994
    Assignee: Mitsubishi Metal Corporation
    Inventors: Ryoji Nakayama, Takuo Takeshita, Tamotsu Ogawa
  • Patent number: 5252549
    Abstract: The present invention is related to a superconductive ceramic wire and a method for making same. According to the first aspect of the invention, there is provided a method for making a superconductive ceramic wire, the method comprising the steps of: (a) preparing a superconductive porous ceramics; (b) depositing lead in the pores of the ceramics; (c) covering the lead-depositted ceramics with a metal; and (d) extending the metal-clad and lead-deposited ceramics. According to the second aspect of the invention, there is provided a superconductive ceramic wire which is obtained by: (a) preparing a superconductive porous ceramics; (b) depositing lead in the pores of the ceramics; (c) covering the lead-depositted ceramics with a metal; and (d) extending the metal-clad lead-depositted ceramics.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: October 12, 1993
    Assignee: Mitsubishi Kinzoku Kabushiki Kaisha
    Inventors: Tetsuro Yamaguchi, Takuo Takeshita, Sadaaki Hagino
  • Patent number: 5250206
    Abstract: A R-Fe-B or R-Fe-Co-B permanent magnet powder excellent in magnetic anisotropy and corrosion resistivity, having powder particles. The powder particles each consist essentially of, in atomic percentage:R: 10-20%B: 3-20%;at least one element selected from the group consisting of Ti, V, Nb, Ta, Al, and Si: 0.001-5.0%; andFe and inevitable impurities: the balance,The R-Fe-Co-B magnet powder further contains 0.1-50% Co.The powder particles each have an aggregated recrystallized structure having a main phase thereof formed by a R.sub.2 Fe.sub.14 B or R.sub.2 (Co,Fe).sub.14 B type intermetallic compound phase having a tetragonal structure. The intermetallic compound phase is formed of recrystallized grains aggregated therein and includes at least 50 volumetric % of recrystallized grains having a ratio b/a smaller than 2 provided that a is designated by the smallest diameter of each of the recrystallized grains, and b is by the largest diameter thereof.
    Type: Grant
    Filed: September 19, 1991
    Date of Patent: October 5, 1993
    Assignee: Mitsubishi Materials Corporation
    Inventors: Ryoji Nakayama, Takuo Takeshita, Tamotsu Ogawa
  • Patent number: 5236889
    Abstract: 1. In the (Bi,Tl)-Ca-(Sr,Ba)-Cu-O based superconducting ceramics production process, a process for preparing superconducting ceramics characterized by(a) providing powders includingi) a compound of Bi oxide or Tl oxide,ii) a Ca compound,iii) an Sr compound or Ba compound, andiv) a Cu compoundas starting powders;(b) compounding and mixing powders from compounds of the starting powders, the compounds each having lower vapor pressure, i.e., powders from compound ii), compound iii), and compound iv) at a compounding ratio to obtain a mixture, and primarily calcining the mixture at a temperature of 850.degree. to 1050.degree. C., to form a Ca--(Sr,Ba)--Cu--O based oxide; and(c) further mixing the Ca--(Sr,Ba)--Cu--O based oxide with a compound having a higher vapor pressure, that is, the powder of compound i), at a compounding ratio, and secondarily calcining at a temperature of 500.degree. to 820.degree. C.
    Type: Grant
    Filed: November 27, 1989
    Date of Patent: August 17, 1993
    Assignee: Mitsubishi Materials Corporation
    Inventors: Tadashi Sugihara, Takuo Takeshita, Yukihiro Ouchi, Takeshi Sakurai
  • Patent number: 5228930
    Abstract: There is disclosed a R-Fe-B or R-Fe-Co-B alloy permanent magnet powder which may contain Ga, Zr or Hf, or may further contain Al, Si or V. Each individual particle of the powder includes a structure of recrystallized grains containing a R.sub.2 Fe.sub.14 B or R.sub.2 (Fe,Co).sub.14 B intermetallic compound phase. The intermetallic compound phase has recrystallized grains of a tetragonal crystal structure having an average crystal grain size of 0.05 to 20 .mu.m. At least 50% by volume of the recrystallized grains of the aggregated structure are formed so that a ratio of the greatest dimension to the smallest dimension is less than 2 for each recrystallized grain. In order to manufacture the magnet powder, regenerative material and alloy material are prepared and their temperature is elevated in a hydrogen atmosphere. Then, the alloy material and the regenerative material are held in the same atmosphere at a temperature of 750.degree. C. to 950.degree. C., and then held in a vacuum at 750.degree. C. to 950.
    Type: Grant
    Filed: July 31, 1990
    Date of Patent: July 20, 1993
    Assignee: Mitsubishi Materials Corporation
    Inventors: Ryoji Nakayama, Takuo Takeshita, Tamotsu Ogawa
  • Patent number: 5211770
    Abstract: A magnetic recording powder for use as a material for magnetic recording media including magnetic tapes and magnetic cards, the powder having a high coercive force at room temperatures and a low Curie point, consists of at least one element selected from the group consisting of Y and rare-earth elements (R): 5-20 atomic %, B: 5-20 atomic %, Mn: 4-20 atomic %; and Fe and inevitable impurities: the balance. If required, the powder may further contain Al: 1-10 atomic %, and/or Cr: 1-10 atomic %. The powder has a mean particle size of 0.5-2 .mu.m and a mean crystal grain size of 0.1-0.4 .mu.m.
    Type: Grant
    Filed: July 29, 1992
    Date of Patent: May 18, 1993
    Assignees: Mitsubishi Materials Corporation, Nippon Telegraph and Telephone Corporation, Dai Nippon Insatsu Kabushiki Kaisha
    Inventors: Ginya Ishiguro, Kouichi Ishiyama, Yoshinari Ishii, Takuo Takeshita, Hachiro Saito, Yasuaki Yoshioka
  • Patent number: 5207981
    Abstract: The present invention provides heat reserving materials comprising alloys of Ru and at least one rare earth metal which are represented by the formula (I):(A.sub.1-x B.sub.x).sub.z Ru.sub.1-y C.sub.ywherein A represents one or two or more of Er, Ho and Dy; B represents one or two or more of the other rare earth metals; C represents one or two or more of Co, Ni, Al, Cu, Pd, Rh, Au, Ag, Cr, Mn, V and B; x is not less than 0 and not more than 0.5; y is not less than 0 and less than 1.0; and z is more than 1.1 and less than 5.0.When the heat reserving materials of the present invention are used in a cryogenic refrigerator, very low temperatures of not higher than 10 K. can be achieved. Specific heat properties of the materials can be varied as desired by adjusting the content ratio of the plural phases each of which has a different magnetic transition temperature.
    Type: Grant
    Filed: September 27, 1991
    Date of Patent: May 4, 1993
    Assignees: Mitsubishi Materials Corporation, Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasuhiro Hanaue, Etsuji Kimua, Takuo Takeshita, Kouichi Ishiyama, Masashi Nagao, Takashi Inaguchi, Hideto Yoshimura
  • Patent number: 5147447
    Abstract: The present invention provides sintered rare earth metal-boron-iron alloy magnets having superior anti-corrosion properties in which the magnetic properties do not deteriorate with time obtained by adding at least one oxide powder chosen from the group including Al, Ga, Ni, Co, Mn, Cr, Ti, V, Nb, Y, Ho, Er, Tm, Lu, as well as Eu, as well as at least one hydride powder chosen from the group including Zr, Ta, Ti, Nb, V. Hf, and Y in an amount totalling from 0.0005 to 3.0 weight % to a R-B-Fe alloy powder; molding; sintering; and then carrying out heat treatment as necessary.
    Type: Grant
    Filed: February 2, 1990
    Date of Patent: September 15, 1992
    Assignee: Mitsubishi Materials Corporation
    Inventors: Takuo Takeshita, Muneaki Watanabe
  • Patent number: 5145835
    Abstract: A process for fabricating worked superconducting ceramic material of a mean grain size not more than 10 um is disclosed, which comprises the steps of: (a) preparing a metal casing containing a starting powder material having a composition for forming an oxide superconductor; (b) calcining the starting powder material contained in the casing at a temperature range of 850.degree. to 950.degree. C.; (c) subjecting said casing to a HIP treatment; (d) subjecting said casing containing hot deformed material to cold deformation processing; and (e) subjecting said casing to stress relief treatment by annealing in the presence of oxygen.
    Type: Grant
    Filed: April 22, 1991
    Date of Patent: September 8, 1992
    Assignee: Mitsubishi Materials Corporation
    Inventors: Takuo Takeshita, Sadaaki Hagino, Tatsuro Ajima, Motokazu Suzuki
  • Patent number: 5124311
    Abstract: There is disclosed the structure of a superconductive wiring fabricated on an insulating substrate comprising a conductive pattern having at least one wiring strip of a superconductive ceramic formed on the insulating substrate and a protective film covering the wiring pattern and formed of a basic oxide, the basic oxide hardly reacts with the superconductive ceramic because of the fact that most of the superconductive ceramics are bases, then the wiring strip is allowed to stay in the superconductive state for a prolonged period of time.
    Type: Grant
    Filed: May 30, 1989
    Date of Patent: June 23, 1992
    Assignee: Mitsubishi Kinzoku K.K.
    Inventors: Satoru Mori, Hideaki Yoshida, Takuo Takeshita, Yoshio Kanda
  • Patent number: 5110374
    Abstract: In a rare earth-iron-boron alloy magnet powder, each individual particle includes a recrystallized grain structure containing a R.sub.2 Fe.sub.14 B intermetallic compound phase as a principal phase thereof, wherein R represents a rare earth element. The intermetallic compound phase are formed of recrystallized grains of a tetragonal crystal structure having an average crystal grain size of 0.05 .mu.m to 50 .mu.m. For producing the above magnet powder, a rear earth-iron-boron alloy material is first prepared. Then, hydrogen is occluded inot the alloy material by holding the material at a temperature of 500.degree. C. to 1,000.degree. C. either in an atmosphere of hydrogen gas or in an atmosphere of hydrogen and inert gases. Subsequently, the alloy material is subjected to dehydrogenation at a temperature of 500.degree. C. to 1,000.degree. C. until the pressure of hydrogen in the atmosphere is decreased to no greater than 1.times.10.sup.-1 torr, and is subjected to cooling.
    Type: Grant
    Filed: June 6, 1990
    Date of Patent: May 5, 1992
    Assignee: Mitsubishi Materials Corporation
    Inventors: Takuo Takeshita, Ryoji Nakayama, Tamotsu Ogawa