Patents by Inventor Bruce J. Pletka

Bruce J. Pletka 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 producing high strength alumina
    Patent number: 5443773
    Abstract: A vacuum hot pressed alumina material having small, isometric grains; a uniform distribution thereof; relatively low, predominantly transgranular porosity; and a density approaching the theoretical density of pure alumina produced by vacuum hot pressing alumina powder which contains at least 98.0% alumina, is substantially free of any sintering aids or any other additives, and has a median particle size less than about 3 microns, in a vacuum hot press operated at a temperature of at least about 1350.degree. C. and a pressure of at least 28 MPa (3500 PSI) for a sintering period of at least 1.5 hours. The vacuum hot pressed alumina material also has compressive strength, flexural strength, impact strength, and wear resistance superior to that for most conventional sintered alumina materials.
    Type: Grant
    Filed: March 14, 1994
    Date of Patent: August 22, 1995
    Assignee: Board of Control of Michigan Technological University
    Inventors: James M. Staehler, William W. Predebon, Bruce J. Pletka
  • High strength alumina and process for producing same
    Patent number: 5352643
    Abstract: A vacuum hot pressed alumina material having small, isometric grains; a uniform distribution thereof; relatively low, predominantly transgranular porosity; and a density approaching the theoretical density of pure alumina produced by vacuum hot pressing alumina powder which contains at least 98.0% alumina, is substantially free of any sintering aids or any other additives, and has a median particle size less than about 3 microns, in a vacuum hot press operated at a temperature of at least about 1350.degree. C. and a pressure of at least 28 MPa (3500 PSI) for a sintering period of at least 1.5 hours. The vacuum hot pressed alumina material also has compressive strength, flexural strength, impact strength, and wear resistance superior to that for most conventional sintered alumina materials.
    Type: Grant
    Filed: November 3, 1992
    Date of Patent: October 4, 1994
    Assignee: Board of Control of Michigan Technological University
    Inventors: James M. Staehler, William W. Predebon, Bruce J. Pletka