Patents by Inventor David S. Duvall

David S. Duvall 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: 4615865
    Abstract: Improved coating compositions are described for the protection of superalloys at elevated temperatures. The coatings of the NiCrAlY or NiCoCrAlY type are significantly improved by the use of higher levels of yttrium.
    Type: Grant
    Filed: July 12, 1983
    Date of Patent: October 7, 1986
    Assignee: United Technologies Corporation
    Inventors: David S. Duvall, Dinesh K. Gupta
  • Patent number: 4585481
    Abstract: Improved coating compositions are described for the protection of superalloys at elevated temperatures. The coatings are of the MCrAlY type where M is nickel or cobalt and are significantly improved by the addition of from 0.1-7% silicon and 0.1-2% hafnium. Coatings of the invention are preferably applied by plasma spraying and as so applied are found to be substantially more effective than prior art coatings.
    Type: Grant
    Filed: August 22, 1983
    Date of Patent: April 29, 1986
    Assignee: United Technologies Corporation
    Inventors: Dinesh K. Gupta, David S. Duvall
  • Patent number: 4457948
    Abstract: Plasma flame sprayed ceramic thermal barrier coatings on metal substrates are treated to make the coatings resistant to damage from thermal cycling. The coating and substrate are heated to a temperature in the range of 820.degree.-1150.degree. C. then are quenched in a medium capable of producing a surface heat flux of at least 1.3.times.10.sup.5 watts/m.sup.2. This causes creation of a fine network of cracks extending from the surface of the coating to the surface of the substrate whereby during thermal cycling, buildup of damaging stresses at the coating-substrate interface is avoided.
    Type: Grant
    Filed: July 26, 1982
    Date of Patent: July 3, 1984
    Assignee: United Technologies Corporation
    Inventors: Duane L. Ruckle, David S. Duvall
  • Patent number: 4419416
    Abstract: Improved coating compositions are described for the protection of superalloys at elevated temperatures. The coatings are of the MCrAlY type where M is nickel or cobalt and are significantly improved by the addition of from 0.1-7% silicon and 0.1-2% hafnium. Coatings of the invention are preferably applied by plasma spraying and as so applied are found to be substantially more effective than prior art coatings.
    Type: Grant
    Filed: August 5, 1981
    Date of Patent: December 6, 1983
    Assignee: United Technologies Corporation
    Inventors: Dinesh K. Gupta, David S. Duvall
  • Patent number: 4213026
    Abstract: A class of age hardenable nickel base alloys for use as filler wires in fusion welding superalloys is described. The alloys contain manganese in levels of from about 0.5 to 3 percent to greatly reduce the incidence of heat-affected zone cracking in the metal being welded. The weld filler alloys also contain significant amounts of aluminum, titanium, tantalum, and columbium, and therefore the resultant welds can be age hardened to relatively high strength levels.
    Type: Grant
    Filed: June 6, 1978
    Date of Patent: July 15, 1980
    Assignee: United Technologies Corporation
    Inventors: David S. Duvall, William H. King, William A. Owczarski
  • Patent number: 4122992
    Abstract: An interlayer for transient liquid phase diffusion bonding of the nickel, cobalt and iron alloys is provided between surfaces to be joined as a thin lamellar composite.
    Type: Grant
    Filed: May 2, 1977
    Date of Patent: October 31, 1978
    Assignee: United Technologies Corporation
    Inventors: David S. Duvall, Daniel F. Paulonis
  • Patent number: 4073639
    Abstract: In filling voids in or between metallic articles, as in the repair of cracks or other surface defects in castings, the void is filled with a powder mix which upon heat treatment fills the void. The filler powder mix is a blend of at least two distinct powder components and in terms of overall composition preferably corresponds to that of article being repaired. The components comprising the mix are selected to provide a transient liquid phase and isothermal resolidification of a portion of the mix at the temperature below the article melting point. A subsequent heat treatment is preferably utilized for homogenization.
    Type: Grant
    Filed: November 24, 1976
    Date of Patent: February 14, 1978
    Assignee: United Technologies Corporation
    Inventors: David S. Duvall, William A. Owczarski, Daniel F. Paulonis, Robert P. Schaefer
  • Patent number: 4008844
    Abstract: In filling voids in or between metallic articles, as in the repair of cracks or other surface defects in castings, the void is filled with a powder mix which upon heat treatment fills the void. The filler powder mix is a blend of at least two distinct powder components and in terms of overall composition preferably corresponds to that of article being repaired. The components comprising the mix are selected to provide a transient liquid phase and isothermal resolidification of a portion of the mix at the temperature below the article melting point. A subsequent heat treatment is preferably utilized for homogenization.
    Type: Grant
    Filed: January 6, 1975
    Date of Patent: February 22, 1977
    Assignee: United Technologies Corporation
    Inventors: David S. Duvall, William A. Owczarski, Daniel F. Paulonis, Robert P. Schaefer
  • Patent number: RE32121
    Abstract: Improved coating compositions are described for the protection of superalloys at elevated temperatures. The coatings are of the MCrAlY type where M is nickel or cobalt and are significantly improved by the addition of from 0.1-7% silicon and 0.1-2% hafnium. Coatings of the invention are preferably applied by plasma spraying and as so applied are found to be substantially more effective than prior art coatings.
    Type: Grant
    Filed: April 24, 1984
    Date of Patent: April 22, 1986
    Assignee: United Technologies Corporation
    Inventors: Dinesh K. Gupta, David S. Duvall