Patents Assigned to Cornell Research
  • Patent number: 4849142
    Abstract: The invention relates to producing relatively flaw free zirconia ceramic shapes requiring little or no matching by superplastic forging of a fully sintered or partially sintered preform. The preform is prepared by providing a starting powder comprising by weight from about 70% to about 100% zirconia and from about 0 to about 30% of stabilizing additives, e.g. commerically available TZ-3Y powder, cold pressing to obtain a preform of green density ranging from about 30% of theoretical density to about 75% of theoretical density and partially or fully sintering at atmospheric pressure, e.g. in argon or air at a temperature ranging from about 900.degree. C. to about 1900.degree. C. The superplastic forging is carried out by isothermally pressing the partially or fully sintered preform into substantially final shape utilizing a temperature and strain rate such that surface cracks do not occur, e.g. utilizing a temperature of 1310.degree. C.
    Type: Grant
    Filed: January 3, 1986
    Date of Patent: July 18, 1989
    Assignees: Jupiter Technologies, Inc., Cornell Research
    Inventors: Prakash C. Panda, Edgar R. Seydel, Rishi Raj