Patents by Inventor Relva C. Buchanan

Relva C. Buchanan 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
  • Patent number: 4283228
    Abstract: Addition of from about 0.1 to about 6.0% by weight of V.sub.2 O.sub.5 to (PZT)lead zirconate-lead titanate powder promotes rapid densification at temperatures below 1000.degree. C. and eliminates the need for PbO atmosphere control. Densification to greater than 98% of theoretical density is achieved with firing times as short as 1-5 minutes. Dielectric properties depend upon the amount of V.sub.2 O.sub.5 added and upon the microstructure developed, but in general are equivalent to those reported for conventional PZT compositions.
    Type: Grant
    Filed: December 5, 1979
    Date of Patent: August 11, 1981
    Assignee: University of Illinois Foundation
    Inventors: Relva C. Buchanan, Dale E. Wittmer
  • Patent number: H987
    Abstract: A ceramic dielectric composition useful in the manufacture of compact ceramic capacitors consisting essentially of barium titanate and zirconium dioxide has a dielectric constant ranging from 1800 to 3500 and a heat dissipation factor, tangent delta, less than 3% over the operating temperature range of electronic circuit components.
    Type: Grant
    Filed: June 12, 1989
    Date of Patent: November 5, 1991
    Inventors: Relva C. Buchanan, Alena K. Maurice