Patents by Inventor Hisae Hirako

Hisae Hirako 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).

  • Process for production of fine .alpha.-alumina powder
    Patent number: 5449389
    Abstract: A process for production of a fine alpha-alumina powder having a specific surface area of not smaller than 10 m.sup.2 /g and superior polishing characteristics is provided, the process comprising heat-treating a mixture of gamma-alumina powder and silica at a temperature at which gamma-alumina is converted to alpha-alumina in the presence of silica, wherein the mixture contains not more than about 10 wt % of silica, based on the weight of the gamma-alumina.
    Type: Grant
    Filed: January 28, 1993
    Date of Patent: September 12, 1995
    Assignee: Mitsubishi Materials Corporation
    Inventors: Motohiko Yoshizumi, Hisae Hirako