Patents by Inventor Nobuyoshi Imaoka

Nobuyoshi Imaoka 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).

  • Publication number: 20230386710
    Abstract: A coated rare earth-iron-nitrogen-based magnetic powder including: a core region; a first coating portion provided outside the core region; and a second coating portion, the core region containing R, Fe, and N, where R represents at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and if Sm is present, Sm constitutes less than 50 atm % of the total R content, the powder including, in an order from the core region, the first coating portion containing P and R, an average atomic concentration of R in the first coating portion being higher than and not higher than twice an average atomic concentration of R in the core region, and the second coating portion having average atomic concentrations of P and R lower than those in the first coating portion, respectively, and containing Fe.
    Type: Application
    Filed: May 26, 2023
    Publication date: November 30, 2023
    Applicant: NICHIA CORPORATION
    Inventors: Jun AKAMATSU, Satoshi ABE, Nobuyoshi IMAOKA, Masahiro ABE
  • Patent number: 11732336
    Abstract: Provided are: a novel magnetic material having high magnetic stability, in particular, having an extremely high saturation magnetization; and a method for producing the same, wherein the magnetic material, due to having a higher saturation magnetization than ferrite magnetic materials and a higher electrical resistivity than existing metallic magnetic materials, resolves problems such as eddy current loss. According to the present invention, Co-ferrite nanoparticles obtained by wet synthesis are reduced in hydrogen and subjected to grain growth, and bcc- or fcc-(Fe, Co) phases and Co-enriched phases are nano-dispersed using phase separation via a disproportionation reaction to prepare a magnetic material powder. In addition, the magnetic material powder is sintered into a solid magnetic material.
    Type: Grant
    Filed: September 20, 2018
    Date of Patent: August 22, 2023
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Shinpei Yamamoto, Nobuyoshi Imaoka, Kimihiro Ozaki
  • Patent number: 11459646
    Abstract: The purpose of the present invention is to provide: a new magnetic material which exhibits high magnetic stability and excellent oxidation resistance and which can achieve both significantly higher saturation magnetization and lower coercive force than a conventional ferrite-based magnetic material by using a magnetic material obtained by nanodispersing ?-(Fe,M) phases and M component-enriched phases (here, the M component is at least one component selected from among Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn and Si); and a method for producing same. This magnetic material powder exhibits high moldability, and is such that ?-(Fe, M) phases and M-enriched phases are nanodispersed by chemically reducing M-ferrite nanoparticles, which are obtained by means of wet synthesis, in hydrogen and utilizing phase separation by means of a disproportionation reaction while simultaneously carrying out grain growth. Furthermore, a solid magnetic material is obtained by sintering this powder.
    Type: Grant
    Filed: September 20, 2018
    Date of Patent: October 4, 2022
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Nobuyoshi Imaoka, Shinpei Yamamoto, Kimihiro Ozaki
  • Patent number: 11331721
    Abstract: Provided are a new, highly magnetically stable magnetic material which has higher saturation magnetization than ferrite-based magnetic materials, and with which problems of eddy current loss and the like can be solved due to higher electric resistivity than that of existing metal-based magnetic materials, and a method for manufacturing the same. A magnetic material powder is obtained by reducing in hydrogen Ni-ferrite nanoparticies obtained by wet synthesis and causing grain growth, while simultaneously causing nanodispersion of an ?-(Fe, Ni) phase and an Ni-enriched phase by means of a phase dissociation phenomenon due to disproportional reaction. The powder is sintered to obtain a solid magnetic material.
    Type: Grant
    Filed: February 23, 2018
    Date of Patent: May 17, 2022
    Assignee: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Shinpei Yamamoto, Nobuyoshi Imaoka, Kimihiro Ozaki
  • Patent number: 11033958
    Abstract: Provided is a new magnetic material with high magnetic stability, as well as a manufacturing method therefor, said magnetic material having a higher saturation magnetization than ferrite-based magnetic materials, and having a higher electrical resistivity than existing metal-based magnetic materials, thus solving problems such as that of eddy current loss. Mn-ferrite nanoparticles obtained through wet synthesis are reduced within hydrogen, and grains are allowed to grow while simultaneously using a phase separation phenomenon due to a disproportionation reaction to produce a magnetic material powder in which an ?-(Fe, Mn) phase and a Mn-enriched phase are nano-dispersed. This powder is then sintered to produce a solid magnetic material.
    Type: Grant
    Filed: March 24, 2017
    Date of Patent: June 15, 2021
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Nobuyoshi Imaoka, Kimihiro Ozaki
  • Patent number: 10978228
    Abstract: Provided is a new magnetic material with high magnetic stability, as well as a manufacturing method therefor, said magnetic material having a higher saturation magnetization than ferrite-based magnetic materials, and having a higher electrical resistivity than existing metal-based magnetic materials, thus solving problems such as that of eddy current loss. Ti-ferrite nanoparticles obtained through wet synthesis are reduced within hydrogen, and grains are allowed to grow while simultaneously using a phase separation phenomenon due to a disproportionation reaction to produce a magnetic material powder in which an ?-(Fe, Ti) phase and a Ti-enriched phase are nano-dispersed. This powder is then sintered to produce a solid magnetic material.
    Type: Grant
    Filed: March 24, 2017
    Date of Patent: April 13, 2021
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Nobuyoshi Imaoka, Kimihiro Ozaki
  • Publication number: 20200265976
    Abstract: Provided are: a novel magnetic material having high magnetic stability, in particular, having an extremely high saturation magnetization; and a method for producing the same, wherein the magnetic material, due to having a higher saturation magnetization than ferrite magnetic materials and a higher electrical resistivity than existing metallic magnetic materials, resolves problems such as eddy current loss. According to the present invention, Co-ferrite nanoparticles obtained by wet synthesis are reduced in hydrogen and subjected to grain growth, and bcc- or fcc-(Fe, Co) phases and Co-enriched phases are nano-dispersed using phase separation via a disproportionation reaction to prepare a magnetic material powder. In addition, the magnetic material powder is sintered into a solid magnetic material.
    Type: Application
    Filed: September 20, 2018
    Publication date: August 20, 2020
    Applicant: National Institute of Advanced Industrial Science and Technology
    Inventors: Shinpei Yamamoto, Nobuyoshi Imaoka, Kimihiro Ozaki
  • Publication number: 20200248288
    Abstract: The purpose of the present invention is to provide: a new magnetic material which exhibits high magnetic stability and excellent oxidation resistance and which can achieve both significantly higher saturation magnetization and lower coercive force than a conventional ferrite-based magnetic material by using a magnetic material obtained by nanodispersing ?-(Fe,M) phases and M component-enriched phases (here, the M component is at least one component selected from among Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn and Si); and a method for producing same. This magnetic material powder exhibits high moldability, and is such that ?-(Fe, M) phases and M-enriched phases are nanodispersed by chemically reducing M-ferrite nanoparticles, which are obtained by means of wet synthesis, in hydrogen and utilizing phase separation by means of a disproportionation reaction while simultaneously carrying out grain growth. Furthermore, a solid magnetic material is obtained by sintering this powder.
    Type: Application
    Filed: September 20, 2018
    Publication date: August 6, 2020
    Applicant: National Institute of Advanced Industrial Science and Technology
    Inventors: Nobuyoshi Imaoka, Shinpei Yamamoto, Kimihiro Ozaki
  • Publication number: 20190375004
    Abstract: Provided are a new, highly magnetically stable magnetic material which has higher saturation magnetization than ferrite-based magnetic materials, and with which problems of eddy current loss and the like can be solved due to higher electric resistivity than that of existing metal-based magnetic materials, and a method for manufacturing the same. A magnetic material powder is obtained by reducing in hydrogen Ni-ferrite nanoparticies obtained by wet synthesis and causing grain growth, while simultaneously causing nanodispersion of an ?-(Fe, Ni) phase and an Ni-enriched phase by means of a phase dissociation phenomenon due to disproportional reaction. The powder is sintered to obtain a solid magnetic material.
    Type: Application
    Filed: February 23, 2018
    Publication date: December 12, 2019
    Applicant: National Institute of Advanced Industrial Science and Technology
    Inventors: Shinpei YAMAMOTO, Nobuyoshi IMAOKA, Kimihiro OZAKI
  • Publication number: 20190105708
    Abstract: Provided is a new magnetic material with high magnetic stability, as well as a manufacturing method therefor, said magnetic material having a higher saturation magnetization than ferrite-based magnetic materials, and having a higher electrical resistivity than existing metal-based magnetic materials, thus solving problems such as that of eddy current loss. Mn-ferrite nanoparticles obtained through wet synthesis are reduced within hydrogen, and grains are allowed to grow while simultaneously using a phase separation phenomenon due to a disproportionation reaction to produce a magnetic material powder in which an ?-(Fe, Mn) phase and a Mn-enriched phase are nano-dispersed. This powder is then sintered to produce a solid magnetic material.
    Type: Application
    Filed: March 24, 2017
    Publication date: April 11, 2019
    Applicant: National Institute of Advanced Industrial Science and Technology
    Inventors: Nobuyoshi Imaoka, Kimihiro Ozaki
  • Publication number: 20190051436
    Abstract: Provided is a new magnetic material with high magnetic stability, as well as a manufacturing method therefor, said magnetic material having a higher saturation magnetization than ferrite-based magnetic materials, and having a higher electrical resistivity than existing metal-based magnetic materials, thus solving problems such as that of eddy current loss. Ti-ferrite nanoparticles obtained through wet synthesis are reduced within hydrogen, and grains are allowed to grow while simultaneously using a phase separation phenomenon due to a disproportionation reaction to produce a magnetic material powder in which an ?-(Fe, Ti) phase and a Ti-enriched phase are nano-dispersed. This powder is then sintered to produce a solid magnetic material.
    Type: Application
    Filed: March 24, 2017
    Publication date: February 14, 2019
    Applicant: National Institute of Advanced Industrial Science and Technology
    Inventors: Nobuyoshi Imaoka, Kimihiro Ozaki
  • Publication number: 20100261038
    Abstract: Provided is a composite magnetic material having high magnetic characteristics and high electrical resistivity to be used for a magnet, especially a composite magnetic material to be suitably used for a rotary motor magnet or the like which functions in a high frequency region. The composite magnetic material for the magnet is provided by covering the surface of a rare earth-iron-nitrogen based magnetic material with a ferrite based magnetic material.
    Type: Application
    Filed: October 31, 2008
    Publication date: October 14, 2010
    Inventors: Nobuyoshi Imaoka, Masanori Abe, Takashi Nakagawa, Masaru Tada
  • Publication number: 20100068512
    Abstract: Disclosed is a magnetic material for a high frequency wave which has high magnetic permeability and small eddy-current loss, particularly a magnetic material for a high frequency wave which can be used suitably in an information device which works in a high frequency field of 1 GHz or higher. Specifically disclosed is a composite magnetic material for a high frequency wave, which comprises a (rare earth element)-(iron)-(nitrogen)-based magnetic material and a (rare earth element)-(iron)-(nitrogen)-based magnetic material whose surface is coated with a ferrite magnetic material.
    Type: Application
    Filed: April 25, 2008
    Publication date: March 18, 2010
    Inventors: Nobuyoshi Imaoka, Masanori Abe, Takashi Nakagawa, Sasaru Tada
  • Patent number: 7560053
    Abstract: Thermoelectric materials with a high Seebeck coefficient and a large power factor are provided. The materials are impact resistant and resistant to heat-distortion. Such materials include a rare earth element, Bi, and Te and have a rhombohedral crystal structure. In some examples, the rare earth element is selected from the group consisting of Ce, Sm and Yb. Such materials can be formed as films with a thickness of from 0.01 to 500 ?m on a resin substrate. Production methods may include laminating different types of layers of thickness of 20 nm or less and heat-treating the resultant composition-modulated composite. The material may be separated from a substrate for sintering.
    Type: Grant
    Filed: February 16, 2006
    Date of Patent: July 14, 2009
    Inventors: Nobuyoshi Imaoka, Isao Morimoto, Lance L. Miller, Robert Schneidmiller, David Charles Johnson
  • Patent number: 7364628
    Abstract: A solid material for a magnet, comprising a rare-earth/iron/nitrogen/hydrogen system magnetic material.
    Type: Grant
    Filed: April 24, 2002
    Date of Patent: April 29, 2008
    Assignee: Asahi Kasei Kabushiki Kaisha
    Inventors: Etsuji Kakimoto, Kiyotaka Dohke, Ichiro Shibasaki, Nobuyoshi Imaoka, Akira Chiba
  • Publication number: 20070034838
    Abstract: Thermoelectric materials with a high Seebeck coefficient and a large power factor are provided. The materials are impact resistant and resistant to heat-distortion. Such materials include a rare earth element, Bi, and Te and have a rhombohedral crystal structure. In some examples, the rare earth element is selected from the group consisting of Ce, Sm and Yb. Such materials can be formed as films with a thickness of from 0.01 to 500 ?m on a resin substrate. Production methods may include laminating different types of layers of thickness of 20 nm or less and heat-treating the resultant composition-modulated composite. The material may be separated from a substrate for sintering.
    Type: Application
    Filed: February 16, 2006
    Publication date: February 15, 2007
    Inventors: Nobuyoshi Imaoka, Isao Morimoto, Lance Miller, Robert Schneidmiller, David Johnson
  • Publication number: 20040149357
    Abstract: A solid material for a magnet, comprising a rare-earth/iron/nitrogen/hydrogen system magnetic material.
    Type: Application
    Filed: October 22, 2003
    Publication date: August 5, 2004
    Inventors: Etsuji Kakimoto, Kiyotaka Dohke, Ichiro Shibasaki, Nobuyoshi Imaoka, Akira Chiba
  • Patent number: 6710238
    Abstract: A thermoelectric material having a high Seeback coefficient and a large power factor and excellent in shock resistance, thermal strain resistance, and formability, and a thermoelectric element are disclosed. The thermoelectric material and thermoelectric element is composed of a multilayered body made up of a laminar body of a semimetal, a metal, or a synthetic resin and a laminar body of a semimetal. The average thickness of the laminar bodies ranges from 0.3 nm to 1000 nm. Embodiments of the combination of the laminar bodies are Bi—Al, Bi-polyamide series resin, and Ag—Fe. Such a multilayered body is manufactured by forming an initial multilayered body composed of all the types of laminar bodies constituting the multilayered body and rolling or uniaxially pressing a stack of such initial multilayered bodies.
    Type: Grant
    Filed: December 2, 2001
    Date of Patent: March 23, 2004
    Assignee: Asahi Kasei Kabushiki Kaisha
    Inventors: Hideo Shingu, Keiichi Ishihara, Nobuyoshi Imaoka, Isao Morimoto, Shozo Yamanaka
  • Patent number: 5164104
    Abstract: A magnetic material represented by the formulaR.sub..alpha. Fe.sub.(100-.alpha.-.beta.-.gamma.-.delta.) N.sub..beta. H.sub..gamma. O.sub..delta.whereinR is at least one rare earth element inclusive of Y;.alpha. is from 5 to 20 atomic percent,.beta. is from 5 to 25 atomic percent,.gamma. is from 0.01 to 5 atomic percent and.delta. is from 3 to 15 atomic percent.From this magnetic material, a bonded magnet can advantageously be obtained, while maintaining excellent magnetic properties of the magnetic material used for the production thereof.
    Type: Grant
    Filed: September 11, 1990
    Date of Patent: November 17, 1992
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Kurima Kobayashi, Takahiko Iriyama, Nobuyoshi Imaoka, Akinobu Sudo, Naoko Kashiwaya