Patents by Inventor Douglas W. Freitag

Douglas W. Freitag 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).

  • Publication number: 20220056281
    Abstract: Devices and methods are provided to apply thin layers of antimicrobial coatings onto a wide variety of substrates and articles. The methods can be performed at moderate temperatures and pressures, allowing for the coating of sensitive substrates and articles.
    Type: Application
    Filed: June 2, 2021
    Publication date: February 24, 2022
    Inventors: Douglas W. FREITAG, Arthur J. GAVRIN
  • Patent number: 5640667
    Abstract: A method of fabricating a fully-dense three-dimensional metal article is disclosed. According to a first embodiment of the invention, the interior portion of the article is formed by way of selective laser sintering, in a cross-section of a layer of powder. After formation of the layer of powder, the laser is directed to form a gas-impervious skin around the interior portion of the article in that layer. The process is repeated, until the article is completed. The article surrounded by the skin is then subjected to hot isostatic pressing to densify the article; the skin, which serves as the "can" for the hot isostatic pressing, may or may not be removed from the article, as desired. According to a second embodiment of the invention, the can is formed first by way of laser generation, and is then filled with the metal powder, prior to hot isostatic pressing.
    Type: Grant
    Filed: November 27, 1995
    Date of Patent: June 17, 1997
    Assignee: Board of Regents, The University of Texas System
    Inventors: Douglas W. Freitag, Joseph J. Beaman, David L. Bourell
  • Patent number: 5358912
    Abstract: A high temperature, high strength in-situ reinforced ceramic composite adapted for use in various applications including missile radomes in which microwave transparency is required in a high temperature environment. The material is manufactured by a pressureless sintering process, in which silicon nitride and barium aluminosilicate are blended together, isostatically pressed into a desired shape and thereafter sintered.
    Type: Grant
    Filed: August 8, 1991
    Date of Patent: October 25, 1994
    Assignee: Loral Vought Systems Corporation
    Inventors: Douglas W. Freitag, Kerry K. Richardson
  • Patent number: 4931241
    Abstract: A process for producing a green composite structure by isostatic compression and filtration. A suspension of colloidal size matrix powders is established in a carrier liquid. The suspension is incorporated into a die chamber having a filter opening containing a filter which is permeable to filtrate from the suspension under applied pressure but substantially impermeable to the matrix powders. An elevated pressure is isostatically imposed on the colloidal suspension within the die chamber. The pressure is maintained for a period of time to expel at least 20% of the liquid originally in the colloidal suspension through the filter opening. A specific die chamber comprises a rigid cage structure and an expandable bladder within the cage structure into which the colloidal suspension is introduced. The cage structure is disposed within a pressure vessel which can be initially evacuated to cause the bladder to conform to the cage structure and then pressurized with fluid for the isostatic compression procedure.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: June 5, 1990
    Assignee: LTV Aerospace and Defense Company
    Inventor: Douglas W. Freitag
  • Patent number: 4840763
    Abstract: A process for the production of reinforced refractory composite structures which may be of high density and shaped in desired three dimensional configurations. The shaped composite structures are produced by forming a suspension of particulate materials including a colloidal refractory power, colloidal sintering aid, and refractory reinforcement whiskers in a carrier liquid. The colloidal suspension is conformed to a desired configuration and brought into contact with a semipermeable membrane. A pressure is imposed on the suspension in the desired configuration to expel liquid from the suspension through the membrane to arrive at a green composite having a density of at least 40% of theoretical density. After drying, the green composite is then sintered under conditions to form an intergranular liquid phase in the composite providing further densification. A specific composite is a silicon carbide reinforced silicon nitride composite.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: June 20, 1989
    Assignee: LTV Aerospace and Defense Company
    Inventor: Douglas W. Freitag