Patents by Inventor Seigo Ohiwa

Seigo Ohiwa 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).

  • Aluminum nitride powder capable of forming colored sintered body and process for preparing same
    Patent number: 5459113
    Abstract: A sinterable aluminum nitride powder composition is prepared by adding about 0.05-10.0 parts by weight of at least one compound selected from the group consisting of calcium tungstate and calcium molybdate and optionally about 1.0-7.0 parts by weight of at least one compound selected from the group consisting of yttria, calcium oxide, and calcium carbonate to 100 parts by weight of an aluminum nitride powder prepared by the alumina reduction method without decarbonization and having a residual carbon content of about 2%-10% by weight. The resulting powdery composition is subjected to mixing and deagglomeration in a dry process so as to form a powder mixture having a bulk density of about 0.3-0.5 g/cm.sup.3, and then to decarbonization by heating in an oxidizing atmosphere. The aluminum nitride powder composition has a pressurized bulk density of about 1.50-1.75 g/cm.sup.3 as measured at a pressure of 500 kg/cm.sup.2 and an average particle diameter of about 1.0-3.0 .mu.
    Type: Grant
    Filed: February 1, 1994
    Date of Patent: October 17, 1995
    Assignee: Sumitomo Metal Ceramics Inc.
    Inventors: Toshio Nozaki, Seigo Ohiwa, Hiroshi Iwase, Masanori Oguni