Patents by Inventor Tetuya Nakazumi

Tetuya Nakazumi 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).

  • Acicular alloy magnetic powder
    Patent number: 5260132
    Abstract: An acicular alloy base magnetic powder comprising iron and cobalt, which has an average particle long axis size of not larger than 0.25 .mu.m, an axial ratio of from 4 to 8, a cobalt content of from 8 to 50% by weight based on the weight of iron and saturation magnetization of at least 120 emu/g after being kept standing at the temperature of 60.degree. C. and relative humidity of 90% for a week, which has improved corrosion resistance and can provide a magnetic recording medium suitable for recording in the short wavelength range.
    Type: Grant
    Filed: May 16, 1991
    Date of Patent: November 9, 1993
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Tetuya Nakazumi, Mikio Kishimoto, Toshinobu Sueyoshi, Seigi Kawarai
  • Acicular alloy containing magnetic recording medium
    Patent number: 5252380
    Abstract: An acicular alloy base magnetic powder comprising iron and cobalt, which has an average particle long axis size of not larger than 0.25 .mu.m, an axial ratio of from 4 to 8, a cobalt content of from 8 to 50% by weight based on the weight of iron and saturation magnetization of at least 120 emu/g after being kept standing at the temperature of 60.degree. C. and relative humidity of 90% for a week, which has improved corrosion resistance and can provide a magnetic recording medium suitable for recording in the short wavelength range.
    Type: Grant
    Filed: January 24, 1992
    Date of Patent: October 12, 1993
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Tetuya Nakazumi, Mikio Kishimoto, Toshinobu Sueyoshi, Seigi Kawarai