Patents by Inventor H. Dale DeFord

H. Dale DeFord 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).

  • Patent number: 4303447
    Abstract: Addition of from about 1.0 to about 15% by weight of a vanadium oxide or boric oxide promoter to a zirconia (ZrO.sub.2) powder promotes rapid densification at temperatures below about 1300.degree. C. For example, a density of greater than 92% of estimated theoretical density can be achieved by addition of 4% by weight of ZrV.sub.2 O.sub.7 to monoclinic ZrO.sub.2 and sintering at 1100.degree. C. for about 24 hours. Sintering at temperatures below about 1150.degree. C. avoids the destructive monoclinic/tetragonal phase transformation and provides for better control of microstructure and composition. A density of greater than 98% of estimated theoretical density can be achieved by addition of from about 2 to about 5% by weight of a boric oxide promoter to stabilized cubic ZrO.sub.2 and sintering at about 1200.degree. C. for about 4 hours.
    Type: Grant
    Filed: April 2, 1980
    Date of Patent: December 1, 1981
    Assignee: University of Illinois Foundation
    Inventors: Relva C. Buchanan, H. Dale DeFord, Anup Sircar